The invention relates to a fan and in particular to an axial-flow fan.
Heat dissipation devices or systems are commonly used in electronic devices. A heat dissipation device can dissipate heat generated by an electronic device, thus preventing the electronic device from overheating or burnout. Heat dissipation devices are particularly important to micro-electronic devices, such as integrated circuits. The dimensions of integrated circuits decrease as circuit density increases and packaging technology evolves. Accordingly, heat per unit area is higher.
Currently, the most commonly used heat dissipation device is a fan. Referring to FIGS. 1 and 2, which are schematic diagrams of conventional fans, in FIG. 1, the conventional fan 10 includes a frame 11, a motor base 12, an impeller 13, a plurality of blades 14, and several ribs 15a. The frame 11 is a casing having an opening, and the motor base 12 is disposed in the frame 11. Each of the rib 15a is connected between the motor base 12 and the frame 11. Alternatively, as shown in FIG. 2, the conventional fan 10 uses static blades 15b instead of ribs to be connected between the motor base 12 and the frame 11. However, an unwanted block 19 is generated where the frame 11 is connected with the rib 15a or the static blade 15b due to molding limitations, thus blocking airflow and producing excess noise when the speed of the fan increases.